Method for producing hydrogen cyanide in a particulate heat exchanger circulated as a moving fluidized bed

Abstract

The invention relates to a process for continuously preparing hydrogen cyanide by reacting ammonia with hydrocarbons, the reaction gas mixture being brought to reaction temperature in the fluidized bed by means of indirect heating by contact with a particulate heat transferrer, and which is characterized in that the heat transferrer is conducted cyclically in a transported fluidized bed, the heat transferrer being heated in an ascending transport stream and being contacted with the reaction gas mixture in a descending transport stream.

1 . A process for continuously preparing hydrogen cyanide by reacting ammonia with at least one hydrocarbon, the process comprising bringing a reaction gas mixture comprising the ammonia and the at least one hydrocarbon to reaction temperature in a transported fluidized bed by through indirect heating by contact with a particulate heat transferrer, wherein
 the particulate heat transferrer is conducted cyclically in the transported fluidized bed,   the particulate heat transferrer is heated in an ascending transport stream, and   the particulate heat transferrer is contacted with the reaction gas mixture in a descending transport stream.   
     
     
         2 . The process according to  claim 1 , wherein the reaction gas mixture comprising ammonia and the at least one hydrocarbon, with or without hydrogen, is converted at a temperature in a range of 750 to 1200° C. 
     
     
         3 . The process according to  claim 1 , wherein a fluidization and heating of the particulate heat transferrer in the ascending transport stream is brought about by a heating gas stream generated by combustion. 
     
     
         4 . The process according to  claim 3 , wherein the heating gas stream is obtained by combusting at least one selected from the group consisting of hydrogen, methane, natural gas, and higher hydrocarbons, or with air, an air-oxygen mixture, or oxygen. 
     
     
         5 . The process according to  claim 1 , wherein a material separation of the particulate heat transferrer and gas stream is effected in each case downstream of the ascending and descending transport streams of the transported fluidized bed. 
     
     
         6 . The process according to  claim 5 , wherein separation of the particulate heat transferrer and gas stream is effected by cyclones. 
     
     
         7 . The process according to  claim 6 , wherein the particulate heat transferrer removed from the gas stream is purged with a purge gas to purge back a gas content of intermediate particles. 
     
     
         8 . The process according to  claim 7 , wherein the purge gas comprises hydrogen, methane, or an offgas of a heating gas stream. 
     
     
         9 . The process according to  claim 1 , wherein the particulate heat transferrer comprises aluminium oxide, aluminium nitride, or a mixed phase of aluminium oxide and aluminium nitride. 
     
     
         10 . The process according to  claim 9 , wherein the particulate heat transferrer is doped with at least one element selected from the group consisting of platinum, palladium, iridium, rhodium, copper, and nickel. 
     
     
         11 . The process according to  claim 1 , wherein the reaction gas mixture comprising ammonia and the at least one hydrocarbon, with or without hydrogen, is converted at a temperature in a range of 800 to 900° C. 
     
     
         12 . The process according to  claim 2 , wherein a material separation of the particulate heat transferrer and gas stream is effected in each case downstream of the ascending and descending transport streams of the transported fluidized bed. 
     
     
         13 . The process according to  claim 3 , wherein a material separation of the particulate heat transferrer and gas stream is effected in each case downstream of the ascending and descending transport streams of the transported fluidized bed. 
     
     
         14 . The process according to  claim 4 , wherein a material separation of the particulate heat transferrer and gas stream is effected in each case downstream of the ascending and descending transport streams of the transported fluidized bed. 
     
     
         15 . The process according to  claim 11 , wherein separation of the particulate heat transferrer and gas stream is effected by cyclones. 
     
     
         16 . The process according to  claim 12 , wherein separation of the particulate heat transferrer and gas stream is effected by cyclones. 
     
     
         17 . The process according to  claim 13 , wherein separation of the particulate heat transferrer and gas stream is effected by cyclones. 
     
     
         18 . The process according to  claim 14 , wherein the particulate heat transferrer removed from the gas stream is purged with a purge gas to purge back a gas content of intermediate particles. 
     
     
         19 . The process according to  claim 15 , wherein the particulate heat transferrer removed from the gas stream is purged with a purge gas to purge back a gas content of intermediate particles. 
     
     
         20 . The process according to  claim 16 , wherein the particulate heat transferrer removed from the gas stream is purged with a purge gas to purge back a gas content of intermediate particles.